The primary purpose of this study is to examine certain non-pesticidal biological effects of chlorinated hydrocarbons in mammalian systems. Emphasis will be placed on the estrogenic effects of chlorinated hydrocarbons, primarily on early biochemical events in estrogenicity of chlorinated hydrocarbons which might involve regulation of cell growth. As part of this investigation, attempts will be made to unveil subtle long range toxic manifestations of chlorinated hydrocarbons. This investigation will explore the possibility that chlorinated hydrocarbons possess antiestrogenic properties and whether their estrogenic or antiestrogenic activities reside in the parent compound or in the respective metabolites(s). It is also planned to determine whether certain "biodegradable" chlorinated hydrocarbons (potential substitutes for DDT and chlordane) exhibit effects of long duration even though their biological half-life is brief. A secondary objective involves the determination whether chlorinated hydrocarbons influence the monooxygenase - mediated metabolism of endogenous compounds, such as prostaglandins.